reset_head(): remove action parameter

The only use of the action parameter is to setup the error messages
for unpack_trees(). All but two cases pass either "checkout" or
"reset". The case that passes "reset --hard" would be better passing
"reset" so that the error messages match the builtin reset command
like all the other callers that are doing a reset. The case that
passes "Fast-forwarded" is only updating HEAD and so the parameter is
unused in that case as it does not call unpack_trees(). The value to
pass to setup_unpack_trees_porcelain() can be determined by checking
whether flags contains RESET_HEAD_HARD without the caller having to
specify it.

Signed-off-by: Phillip Wood <phillip.wood@dunelm.org.uk>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

builtin/rebase.c

@@ -583,7 +583,7 @@ static int move_to_original_branch(struct rebase_options *opts)
 		    opts->head_name, oid_to_hex(&opts->onto->object.oid));
 	strbuf_addf(&head_reflog, "rebase finished: returning to %s",
 		    opts->head_name);
-	ret = reset_head(the_repository, NULL, "", opts->head_name,
+	ret = reset_head(the_repository, NULL, opts->head_name,
 			 RESET_HEAD_REFS_ONLY,
 			 orig_head_reflog.buf, head_reflog.buf,
 			 DEFAULT_REFLOG_ACTION);
@@ -674,7 +674,7 @@ static int run_am(struct rebase_options *opts)
 		free(rebased_patches);
 		strvec_clear(&am.args);
 
-		reset_head(the_repository, &opts->orig_head, "checkout",
+		reset_head(the_repository, &opts->orig_head,
 			   opts->head_name, 0,
 			   "HEAD", NULL, DEFAULT_REFLOG_ACTION);
 		error(_("\ngit encountered an error while preparing the "
@@ -820,7 +820,7 @@ static int checkout_up_to_date(struct rebase_options *options)
 	strbuf_addf(&buf, "%s: checkout %s",
 		    getenv(GIT_REFLOG_ACTION_ENVIRONMENT),
 		    options->switch_to);
-	if (reset_head(the_repository, &options->orig_head, "checkout",
+	if (reset_head(the_repository, &options->orig_head,
 		       options->head_name, RESET_HEAD_RUN_POST_CHECKOUT_HOOK,
 		       NULL, buf.buf, DEFAULT_REFLOG_ACTION) < 0)
 		ret = error(_("could not switch to %s"), options->switch_to);
@@ -1272,7 +1272,7 @@ int cmd_rebase(int argc, const char **argv, const char *prefix)
 		rerere_clear(the_repository, &merge_rr);
 		string_list_clear(&merge_rr, 1);
 
-		if (reset_head(the_repository, NULL, "reset", NULL, RESET_HEAD_HARD,
+		if (reset_head(the_repository, NULL, NULL, RESET_HEAD_HARD,
 			       NULL, NULL, DEFAULT_REFLOG_ACTION) < 0)
 			die(_("could not discard worktree changes"));
 		remove_branch_state(the_repository, 0);
@@ -1290,7 +1290,7 @@ int cmd_rebase(int argc, const char **argv, const char *prefix)
 
 		if (read_basic_state(&options))
 			exit(1);
-		if (reset_head(the_repository, &options.orig_head, "reset",
+		if (reset_head(the_repository, &options.orig_head,
 			       options.head_name, RESET_HEAD_HARD,
 			       NULL, NULL, DEFAULT_REFLOG_ACTION) < 0)
 			die(_("could not move back to %s"),
@@ -1759,7 +1759,7 @@ int cmd_rebase(int argc, const char **argv, const char *prefix)
 
 	strbuf_addf(&msg, "%s: checkout %s",
 		    getenv(GIT_REFLOG_ACTION_ENVIRONMENT), options.onto_name);
-	if (reset_head(the_repository, &options.onto->object.oid, "checkout", NULL,
+	if (reset_head(the_repository, &options.onto->object.oid, NULL,
 		       RESET_HEAD_DETACH | RESET_ORIG_HEAD |
 		       RESET_HEAD_RUN_POST_CHECKOUT_HOOK,
 		       NULL, msg.buf, DEFAULT_REFLOG_ACTION))
@@ -1777,7 +1777,7 @@ int cmd_rebase(int argc, const char **argv, const char *prefix)
 		strbuf_addf(&msg, "rebase finished: %s onto %s",
 			options.head_name ? options.head_name : "detached HEAD",
 			oid_to_hex(&options.onto->object.oid));
-		reset_head(the_repository, NULL, "Fast-forwarded", options.head_name,
+		reset_head(the_repository, NULL, options.head_name,
 			   RESET_HEAD_REFS_ONLY, "HEAD", msg.buf,
 			   DEFAULT_REFLOG_ACTION);
 		strbuf_release(&msg);

reset.c

@@ -8,7 +8,7 @@
 #include "tree.h"
 #include "unpack-trees.h"
 
-int reset_head(struct repository *r, struct object_id *oid, const char *action,
+int reset_head(struct repository *r, struct object_id *oid,
 	       const char *switch_to_branch, unsigned flags,
 	       const char *reflog_orig_head, const char *reflog_head,
 	       const char *default_reflog_action)
@@ -23,7 +23,7 @@ int reset_head(struct repository *r, struct object_id *oid, const char *action,
 	struct lock_file lock = LOCK_INIT;
 	struct unpack_trees_options unpack_tree_opts = { 0 };
 	struct tree *tree;
-	const char *reflog_action;
+	const char *action, *reflog_action;
 	struct strbuf msg = STRBUF_INIT;
 	size_t prefix_len;
 	struct object_id *old_orig = NULL, oid_old_orig;
@@ -50,6 +50,7 @@ int reset_head(struct repository *r, struct object_id *oid, const char *action,
 	if (refs_only)
 		goto reset_head_refs;
 
+	action = reset_hard ? "reset" : "checkout";
 	setup_unpack_trees_porcelain(&unpack_tree_opts, action);
 	unpack_tree_opts.head_idx = 1;
 	unpack_tree_opts.src_index = r->index;

reset.h

@@ -12,7 +12,7 @@
 #define RESET_HEAD_REFS_ONLY (1<<3)
 #define RESET_ORIG_HEAD (1<<4)
 
-int reset_head(struct repository *r, struct object_id *oid, const char *action,
+int reset_head(struct repository *r, struct object_id *oid,
 	       const char *switch_to_branch, unsigned flags,
 	       const char *reflog_orig_head, const char *reflog_head,
 	       const char *default_reflog_action);

sequencer.c

@@ -4137,8 +4137,7 @@ void create_autostash(struct repository *r, const char *path,
 			    path);
 		write_file(path, "%s", oid_to_hex(&oid));
 		printf(_("Created autostash: %s\n"), buf.buf);
-		if (reset_head(r, NULL, "reset --hard",
-			       NULL, RESET_HEAD_HARD, NULL, NULL,
+		if (reset_head(r, NULL, NULL, RESET_HEAD_HARD, NULL, NULL,
 			       default_reflog_action) < 0)
 			die(_("could not reset --hard"));